With the development of digital camera manufacturing technologies, small-size and lightweight camera lens assemblies have emerged, which allow cameras to be mounted on portable communication devices, such that portable communication devices having optical lenses and camera lens assemblies mounted thereon have come into wide use.
The camera lens assembly has been miniaturized to be mounted on a portable communication device, and the miniaturized camera lens assembly should be structured to properly realize performance. Together with magnification, another key factor for defining performance of the camera lens assembly is resolution. As the resolution increases, an object of an object becomes clear, such that even the details of the object can be observed. The camera lens assembly can adjust a focal length between an image sensor and a lens, and the camera lens assembly can show maximal resolution at the optimal focal length.
As shown in FIG. 1, a camera lens assembly 1 is structured as described below. The camera lens assembly 1 includes a printed circuit board 2 including an image sensor 2a, a main frame 3, a lens assembly 4, which is provided in the main frame 3 and has a lens (not shown), a driving portion 5 for driving the lens assembly 4 up and down along an optical axis, a guide portion 6 provided between the lens assembly 4 and the driving portion 5, and a cover portion 7 provided on the lens assembly 4.
As shown in FIGS. 1 and 2, the driving portion 5 includes a magnetic object 5a disposed on the lens assembly 4, a coil 5b which is disposed on the main frame 3 in such a way to face the magnetic object 5a and is provided on the center of the magnetic object 5a, a yoke 5c which is fixed on the main frame 3 and is disposed with the coil 5b placed therebetween in such a way to face the magnetic object 5a, and a position sensor 5d which is provided in the yoke 5c and the coil 5b to detect a position of the magnetic object 5a. The driving portion 5 stops the lens assembly 4 at a preset position by an attractive force between the magnetic object 5a and the yoke 5c when power is not supplied to the coil 5b, and generates an electric field and drives the lens assembly 4 through interaction between the electric field and a magnetic field of the magnetic object 5a when the power is supplied to the coil 5b. The position sensor 5d includes a hall sensor for sensing a position change of the magnetic object 5a. 
As shown in FIG. 1, the guide portion 6 includes a pair of guide members 6a provided in the driving portion 5, a pair of support members 6b provided in the lens assembly 4 to correspond to the guide members 6a, and a plurality of balls 6c provided between the guide members 6a and the support members 6b. The support members 6b are disposed to face the guide members 6a, and maintain spaced apart from the guide members 6a by the balls 6c. 
A related structure of the camera lens assembly is disclosed in Korean Patent Registration No. 10-1041473 (registered on Jun. 8, 2011).
However, in the driving portion of the conventional camera lens assembly, when the power is not supplied to the coil, the center of the magnetic object and the center of the coil coincide with each other due to an influence of the attractive force between the magnetic object and the yoke. In this case, the position sensor provided in the coil cannot detect an accurate focal length position in initial driving due to the influence of the attractive force, and if the current is supplied to the coil when the center of the magnetic object and the center of the coil coincide with each other, the position sensor disposed on the center of the coil cannot detect an accurate focal length position in initial driving due to an influence of the electric field induced by the coil, resulting in degradation of an initial resolution of the camera lens assembly.
Moreover, the position sensor may malfunction due to the influence of the electric field of the coil.
Therefore, there is a need for an apparatus for disposing the position sensor and the coil eccentrically from the center of the magnetic object such that they can escape from the influence of the attractive force between the magnetic object and the yoke and the influence of the electric field generated in the coil.